Turbos to Create A Jet

P M V SubbaraoProfessor

Mechanical Engineering Department

A Techno-economically Feasible Creation of Strong and Reliable Muscles for the

Aircraft……

The Concept of Turbo Technology

• A control volume based engine to create Jet.

• Turbo-machinery execute -vdp work.

• Force or torque is generated with steady flow.

• Continuous transfer & conversion of energy is possible at steady flow and steady state.

• Basic Architecture is:

Open Cycle Using Turbos

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5 : Jet

5: Jet

Necessity is the Mother of Invention !?!?!??!

Gas Turbine Technology

• 1791: A patent was given to John Barber, an Englishman, for the first true gas turbine.

• His invention had most of the elements present in the modern day gas turbines.

• The turbine was designed to power a horseless carriage. • 1872: The first true gas turbine engine was designed by Dr

Franz Stikze, but the engine never ran under its own power. • 1903: A Norwegian, Ægidius Elling, was able to build the first

gas turbine that was able to produce more power than needed to run its own components, which was considered an achievement in a time when knowledge about aerodynamics was limited.

• Using rotary compressors and turbines it produced 11 hp (massive for those days).

• He further developed the concept, and by 1912 he had developed a gas turbine system with separate turbine unit and compressor in series, a combination that is now common.

• 1914: Application for a gas turbine engine filed by Charles Curtis.

• 1918: One of the leading gas turbine manufacturers of today, General Electric, started their gas turbine division.

• 1920: The practical theory of gas flow through passages was developed into the more formal (and applicable to turbines) theory of gas flow past airfoils by Dr A. A. Griffith.

THE WORLD‘S FIRST INDUSTRIAL GAS TURBINE SET – GT NEUCHÂTEL

4 MW GT for Power Generation

Gas Turbine Power Generation

• Experience gained from a large number of exhaust-gas turbines for diesel engines, a temp. of 538°C was considered absolutely safe for uncooled heat resisting steel turbine blades.

• This would result in obtainable outputs of 2000-8000 KW with compressor turbine efficiencies of 73-75%, and an overall cycle efficiency of 17-18%.

• First Gas turbine electro locomotive 2500 HP ordered from BBC by Swiss Federal Railways.

• The advent of high pressure and temperature steam turbine with regenerative heating of the condensate and air pre-heating, resulted in coupling efficiencies of approx. 25%.

• The gas turbine having been considered competitive with steam turbine plant of 18% which was considered not quite satisfactory.

A Death Leading to New Life

• The Gas turbine was unable to compete with “modern” base load steam turbines of 25% efficiency.

• There was a continuous development in steam power plant which led to increase of Power Generation Efficiencies of 35%+

• This hard reality required consideration of a different application for the gas turbine.

• 1930: Sir Frank Whittle patented the design for a gas turbine for jet propulsion.

Turbojets

• As invented by Hans Von Ohain &Frank Whittle.

Typical Turbojet

Schematics

Turbojets - Basic Operating Features

• Five basic components:– intake: captures air and efficiently delivers it to compressor.

– compressor: increases air pressure and temperature.

– combustor: adds kerosene to the air and burns the mixture to increase the temperature and energy levels further.

– turbine: extracts energy from the gases to drive the compressor via a shaft.

– nozzle: accelerates the gases further.

• High levels of engineering required for efficient operation, especially for compressor and turbine - therefore costly compared with rocket.

World's first operational jet engine

• Dimensions: 1.48 m long, 0.93 m diameter

• Weight: 360 kg

• Thrust: 450 kgf (4.4 kN) @ 13,000 rpm and 800 km/h

• Compression ratio: 2.8:1

• Specific fuel consumption: 2.16 gal/(lb·h) [18.0 L/(kg·h)]

World's first Aircraft : He178

• General characteristics

• Crew: One

• Length: 7.48 m (24 ft 6 in)

• Wingspan: 7.20 m (23 ft 3 in)

• Height: 2.10 m (6 ft 10 in)

• Wing area: 9.1 m² (98 ft²)

• Empty weight: 1,620 kg (3,572 lb)

• Max takeoff weight: 1,998 kg (4,405 lb)

• Powerplant: 1× HeS 3 turbojet, 4.4 kN (992 lbf)

• Performance

• Maximum speed: 698 km/h (380 mph)

• Range: 200 km (125 mi)

Present Turbojet Engines

• The Rolls-Royce/Snecma Olympus 593 was a reheated (afterburning) turbojet which powered the supersonic airliner Concorde.

• General characteristics

• Type: Turbojet

• Length: 4039 mm (159 in)

• Diameter: 1212 mm (47.75 in)

• Dry weight: 3175 kg (7,000 lb)

• Components

• Compressor: Axial flow, 7-stage low pressure, 7-stage high pressure

• Combustors: Nickel alloy construction annular chamber, 16 vapourising burners, each with twin outlets

• Turbine: High pressure single stage, low pressure single stage

• Fuel type: Jet A1

• Performance

• Maximum Thrust: 169.2 kN (38,050 lbf)

• Overall pressure ratio: 15.5:1

• Specific fuel consumption: 1.195 (cruise), 1.39 (SL) lb/(h·lbf)

• Thrust-to-weight ratio: 5.4

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Turbojets for Guided Weapons

• Jet velocity: 350 - 1200 m/s.

• Better propulsive efficiency than rockets (lower than turbofans).

• Compact & low weight.

• More complex, costly and unreliable than rockets.

HarpoonTeledyne J402-CA-400

Harpoon : General Characteristics

• Primary function: Air-, surface-, or submarine-launched anti-surface (anti-ship) missile

• Contractor: The McDonnell Douglas Astronautic Company - East

• Power plant: Teledyne Teledyne J402 turbojet, 660 lb (300 kg)-force (2.9 kN) thrust, and a solid-propellant booster for surface and submarine launches.

• Length:

– Air launched: 3.8 metres (12 ft) 7 in)

– Surface and submarine launched: 4.6 metres (15 ft)

• Weight:

– Air launched: 519 kilograms (1,140 lb)

– Submarine or ship launched from box or canister launcher: 628 kilograms (1,380 lb)

• Diameter: 340 millimetres (13 in)

• Wing span: 914 millimetres (36.0 in)

• Maximum altitude: 910 metres (3,000 ft) with booster fins and wings

• Range: Over-the-horizon (approx 50 nautical miles)

– AGM-84D: 220 km (120 nmi)

– RGM/UGM-84D: 140 km (75 nmi)

– AGM-84E: 93 km (50 nmi)

– AGM-84F: 315 km (170 nmi)

– AGM-84H/K: 280 km (150 nmi)

• Speed: High subsonic, around 850 km/h (460 knots, 240 m/s, or 530 mph)

• Guidance: Sea-skimming cruise monitored by radar altimeter, active radar terminal homing

• Warhead: 221 kilograms (490 lb), penetration high-explosive blast

• Unit cost: US$720,000

Teledyne CAE J402-CA-400

• Dimensions:Length 74.8 cm (29.44 in.), Width 31.8 cm (12.52 in.

• Physical Description:Type: Turbojet

• Thrust/speed: 2,937 N (660 lb) at 41,200 rpm

• Compressor: 1-stage axial flow, 1-stage centrifugal flow

• Combustor: annular

• Turbine: 1-stage axial flow

• Manufacturer: Teledyne CAE, Toledo

Micro-turbojets for Weapons

Variation of Jet Technologies

Thermal Energy Distribution

Turbofans

• Compromise between turbojet and turboprop with propeller now a fan enclosed within the engine.

• Two air streams passing through engine, one of which bypasses internal core.

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Turbofans - Basic Operating Features

• Similar to turbojet but turbine split into two with low pressure turbine used to drive separate fan ahead of compressor via twin-shaft arrangement.

• Bypass effect increases the available mass flow rate and thus reduces the jet velocity needed for a given amount of thrust (improves propulsive efficiency).

Turbofan

• The Pratt & Whitney F119 is an afterburning turbofan engine developed for the Lockheed Martin F-22 Raptor.

• The engine delivers thrust in the 35,000 lbf (160 kN) class, and is designed for supersonic flight without the use of afterburner.

• Delivering almost 22% more thrust with 40% fewer parts than conventional, fourth-generation military aircraft engine models, the F119 allows sustained supercruise speeds of up to Mach 1.72.

Specifications F119

• General characteristics

• Type: Twin-Spool, Augmented Turbofan

• Length: 16 ft 11 in (5.16 m)

• Diameter:

• Dry weight: 3,900 lb

• Components

• Compressor: Twin Spool/Counter Rotating/Axial Flow/Low Aspect Ratio

• Combustors: Annular Combustor

• Turbine: Axial Flow/Counter-Rotating

• Nozzle: Two Dimensional Vectoring Convergent/Divergent

• Performance

• Maximum Thrust: >35,000 lbf (156 kN) (with afterburner)

• Thrust-to-weight ratio: 9:1

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Turbofans for GW

• Very good propulsive efficiency and low specific fuel consumption

• Only very long range applications

• Large volume and difficult to design to small scales.

• Jet velocity: 200 – 600 m/s

• Bypass ratio: 0.5:1 (much higher in aircraft applications)

Tomahawk

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Intakes - Turbofan/Turbojet

Teledyne J402

Williams F107

Tomahawk/ALCM

Harpoon/SLAM

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Turboprops• Turbine extracts most of the jet thrust to run a

propeller at the front, via a gear box.

• Limited GW applications (possibly future UAV’s).

• Mainly low-speed aircraft applications (limited to about Mach 0.6). Typical Turboprop Schematic